HD recognized, but not accessible.

Okay, so it looks like I just needed to Initialize the disk. I couldn't find directions for doing this anywhere, but the manufacturer (LaCie) came through for me and told me exactly how to do it. There directions follow:

-Right-click on My Computer and select Manage.
-On the left, in the Storage folder, click on Disk Management.
-If the Write Signature Wizard opens, follow the wizard.
-If the wizard did not open, you can right-click on the disk "Unknown" in the bottom part of the Computer Management window and select Write Signature and OK. (If the disk is not labeled as "unknown" then it has already been initialized and you can proceed with formatting).
-Then proceed with formatting below.

Formatting:
-Now right-click on the unallocated space of the disk and select New Partition.
-The New Partition Wizard will open.
-Click through the wizard. You can leave most settings at their defaults, but make sure to select the option to perform a Quick Format.

This will perform a quick format, that will only take a few moments (depending on the size of the drive). Once completed, your disk should be accessible with the chosen drive letter in My Computer and Explorer. Okay, so it looks like I just needed to Initialize the disk. I couldn't find directions for doing this anywhere, but the manufacturer (LaCie) came through for me and told me exactly how to do it. There directions follow: -Right-click on My Computer and select Manage. -On the left, in the Storage folder, click on Disk Management. -If the Write Signature Wizard opens, follow the wizard. -If the wizard did not open, you can right-click on the disk "Unknown" in the bottom part of the Computer Management window and select Write Signature and OK. (If the disk is not labeled as "unknown" then it has already been initialized and you can proceed with formatting). -Then proceed with formatting below. Formatting: -Now right-click on the unallocated space of the disk and select New Partition. -The New Partition Wizard will open. -Click through the wizard. You can leave most settings at their defaults, but make sure to select the option to perform a Quick Format. This will perform a quick format, that will only take a few moments (depending on the size of the drive). Once completed, your disk should be accessible with the chosen drive letter in My Computer and Explorer.